In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especia...In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especially for developing new reaction pathway to afford the functional heterocycle compounds with aggregation-induced emission(AIE)property has been rarely reported.In present work,the multi-site functionalization of in situ generated alkenes with indoles has been developed for the synthesis of diversely functionalized carbazoles through the synergistic construction of multiple C–C bonds and C=O bond.A proposed reaction sequence involving C–H alkenylation/radical oxygen atom transfer/Diels-Alder cycloaddition/dehydrogenative aromatization was supported by experiments and density functional theory calculations.Further derivative carbazole-linked-quinoxaline skeletons represent a class of AIEgens with acceptor-donor-acceptor configuration,which generated the desired twisted intramolecular charge transfer(TICT)AIE properties and could be used as fluorescent probes for detecting the micrometer-sized phase separation of polymer blends.The protocol provides a concise route for the synthesis and application of carbazole-based AIE luminogens.展开更多
Density functional theory calculations have been performed to investigate the dipeptide phosphinecatalyzed hydroamination of enones with pyridazinones.The computations reveal that a number of the N-H...O hydrogen-bond...Density functional theory calculations have been performed to investigate the dipeptide phosphinecatalyzed hydroamination of enones with pyridazinones.The computations reveal that a number of the N-H...O hydrogen-bonding interactions with the pyridazinone moiety and the C–H...O hydrogenbonding interactions with the enone moiety are present in the enantioselectivity-determining Michael addition transition states.The experimentally-observed catalyst-controlled enantiodivergence is mainly attributed to the significant impact of the substituent of the amide moiety of the dipeptide phosphine on the relative strength of the N-H...O hydrogen-bonding interactions,which was found to affect the Si face attack transition state,enabling the enantioselectivity switch upon change of chiral dipeptide phosphine catalyst.展开更多
Density functional theory calculations have been performed to investigate the nickel-catalyzed[3+2]cycloaddition of cyclopropenones andα,β-unsaturated ketones.The computations show that the overall catalytic cycle c...Density functional theory calculations have been performed to investigate the nickel-catalyzed[3+2]cycloaddition of cyclopropenones andα,β-unsaturated ketones.The computations show that the overall catalytic cycle consists of four major steps,including:(1)C-C oxidative addition of the cyclopropenone to afford the four-membered nickelacycle,(2)isomerization,(3)migratory insertion via a 4,1-insertion fashion,and(4)C-C reductive elimination to deliver the[3+2]cycloaddition product.The enantioselectivity is mainly attributed to the p-p interaction between the diphenylcyclopropenone moiety and the phenyl substituent of the oxazoline ring of the ligand.The chemoselectivity of the C=O versus C=C insertion was rationalized in terms of the steric effect.展开更多
Density functional theory calculations have been performed to investigate the copper-catalyzed borocyanation of 1-aryl-1,3-butadienes.The computations show that the regio-and enantioselectivity is determined by the bo...Density functional theory calculations have been performed to investigate the copper-catalyzed borocyanation of 1-aryl-1,3-butadienes.The computations show that the regio-and enantioselectivity is determined by the borocupration step.The π-electron withdrawing aryl group at the C' atom makes the C4 atom more electrophilic than the other carbon atoms,which together with the steric repulsion around the forming C-B bond,re sults in the experimentally observed exclusive 4,3-regioselectivity.The origins of the enantioselectivity were attributed to the steric effect and π-π stacking interaction between the butadiene moiety and the ligand.展开更多
The rhodium-catalyzed formal C（sp^3）-H activation/spiroannulation of α-arylidene pyrazolones with alkynes was investigated by means of density functional theory calculations. The calculations indicate that the spir...The rhodium-catalyzed formal C（sp^3）-H activation/spiroannulation of α-arylidene pyrazolones with alkynes was investigated by means of density functional theory calculations. The calculations indicate that the spiroannulation through the proposed C-C reductive elimination is kinetically unfeasible, Instead, the C-C coupling from the eight-membered rhodacycle was proposed to account for the experimental results. The overall catalytic cycle consists of six steps： （1） the keto-enol isomerization; （2） the O-H deprotonation, （3） the C（sp^2）-H bond cleavage; （4） the migratory insertion of alkyne into the Rh-C bond; （5） the C-C coupling and （6） the regeneration of the active catalyst.展开更多
The development of olefin hydroacylation with easily accessible acyl reagents in a regioselective manner is highly desirable yet challenging.Herein,we report the hydroacylation of alkenes using acid chlorides as both ...The development of olefin hydroacylation with easily accessible acyl reagents in a regioselective manner is highly desirable yet challenging.Herein,we report the hydroacylation of alkenes using acid chlorides as both acyl reagents and endogenous oxidants through a hydrogen atom transfer pathway.Exclusive Markovnikov hydroacylation of a wide range of alkenes,including terminal,internal,1,1-disubstituted alkenes,and even light gaseous olefins,with aryl and alkyl acid chloride,was achieved with the use of a biquinoline ligand.The direct and step-economy hydroacylation reveals a distinct regioselectivity and ligand dependence compared to traditional NiH chemistry.This protocol has attractive features such as the low cost,broad substrate scope,mild conditions,and easy operation,providing an efficient and modular access to branched ketones with diverse architectures.Density functional theory calculations suggest that the reaction proceeds via a hydrogen atom transfer(HAT)mechanism followed by outer-sphere C–C reductive elimination.展开更多
Chiralγ-amino acids are among the most valuable and ubiquitous structural units in natural products,pharmaceuticals and many physiologically active compounds.Herein,we demonstrate a convenient synthetic approach to c...Chiralγ-amino acids are among the most valuable and ubiquitous structural units in natural products,pharmaceuticals and many physiologically active compounds.Herein,we demonstrate a convenient synthetic approach to chiralγ-amino acid structures via an asymmetric aryl-aminoalkylation of alkenes enabled by a dual photoredox/nickel catalysis.Taking advantage of the mild and redox-neutral condition,high levels of enantiocontrol ofα-carbonyl benzylic stereocenters are obtained.Experimental and computational mechanistic studies were performed to gain insights into the mechanism and origin of enantioselectivity.The results reveal that the reaction follows a Ni(0)/Ni(I)/Ni(III)/Ni(I)catalytic cycle and C-X bond oxidative addition is the enantiodetermining step.展开更多
Density functional theory calculations were performed to investigate the iridium-catalyzed atroposelective intermolecular C-H silylation of 2-arylisoquinolines.The Ir(Ⅲ)hydride species was identified as the active ca...Density functional theory calculations were performed to investigate the iridium-catalyzed atroposelective intermolecular C-H silylation of 2-arylisoquinolines.The Ir(Ⅲ)hydride species was identified as the active catalyst species of the reaction.The computations show that the reaction occurs through the Ir(Ⅲ)/Ir(Ⅴ)catalytic cycle.The C(sp^(2))-H oxidative addition represents the rate-and enantioselectivity-determining step.The distortion/interaction and structural analyses reveal that the BINEPINE skeleton of the PSiSi ligand creates an axially chiral pocket for the C-H oxidative addition,providing a ligand-enabled axial chirality transfer strategy responsible for the observed enantioselectivity.The match/mismatch in axial chirality between reacting 2-arylisoquinolines and the BINEPINE skeleton of the PSiSi ligand plays a key role in governing enantioselectivity.展开更多
The Ni-catalyzed highly selective diborylative cyclization of 1,6-enynes with diboron reagent has been developed. When pinB-Bdan was used, multiple types of boron-containing functional groups could be installed into o...The Ni-catalyzed highly selective diborylative cyclization of 1,6-enynes with diboron reagent has been developed. When pinB-Bdan was used, multiple types of boron-containing functional groups could be installed into organic molecule with great chemoselectivity and regioselectivity though this reaction. Meanwhile, if B_2pai_2 was employed, the asymmetric diborylative cyclization could be well induced by using strategy of dynamic kinetic resolution. Importantly, the above reactions could afford desired product with 100% atomic economy, and could be compatible with different series of substituents. The studies of further transformation well illustrated that different type products could serve diverse synthetic strategy. Notably, the reaction mechanism was intensively studied by density functional theory(DFT) calculations, which could reveal the mechanism of regio- and enantio-selective control.展开更多
The palladium-catalyzed borylative cyclization via C—H activation has been developed.By this chemistry,the indole-fused dihydro-pyrrole motif,which is a kind of important unit in natural products and bio-active molec...The palladium-catalyzed borylative cyclization via C—H activation has been developed.By this chemistry,the indole-fused dihydro-pyrrole motif,which is a kind of important unit in natural products and bio-active molecules,could be constructed and installed with a boric ester group.Furthermore,the utilities of products have been illustrated by the study of further transformations.Importantly,by using chiral ligand,the enantioselectivity of this borylative cyclization reaction could be controlled.Moreover,the borylative mechanism,which should proceed through a Pd(II)/Pd(IV)catalytic cycle,has been proposed based on the DFT calculations.展开更多
Objective:In this study,we summarize the clinical characteristics and neonatal outcomes of patients with pregnancy luteomas that were identified incidentally at cesarean section in our hospital.We also provide a revie...Objective:In this study,we summarize the clinical characteristics and neonatal outcomes of patients with pregnancy luteomas that were identified incidentally at cesarean section in our hospital.We also provide a review of the existing literature relating to this condition.Methods:A total of seven cases of pregnancy luteoma were enrolled from our hospital into this retrospective study between March 2013 and February 2018.We then evaluated the clinical characteristics and neonatal outcomes of these patients.Results:All seven patients with pregnancy luteomas found incidentally during Cesarean sections at term as a result of obstetric indications.These masses were unilateral and ranged from 2 to 10 cm in size.All patients underwent partial ovariectomies or oophorocystectomy due to presumptive benign ovarian tumors.Two patients had gestational diabetes and one patient had gestational hypertension.One patient developed hirsutism and a deepened voice.Of the seven newborns,three were girls and four were boys.Physical examinations of the newborns were normal and no virilization was detected among the infant girls.Conclusion:Pregnancy luteoma may be more common than expected.Better strategies are now needed to educate obstetricians about the clinical features of pregnancy luteoma so that they can avoid unnecessary surgery.展开更多
文摘In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especially for developing new reaction pathway to afford the functional heterocycle compounds with aggregation-induced emission(AIE)property has been rarely reported.In present work,the multi-site functionalization of in situ generated alkenes with indoles has been developed for the synthesis of diversely functionalized carbazoles through the synergistic construction of multiple C–C bonds and C=O bond.A proposed reaction sequence involving C–H alkenylation/radical oxygen atom transfer/Diels-Alder cycloaddition/dehydrogenative aromatization was supported by experiments and density functional theory calculations.Further derivative carbazole-linked-quinoxaline skeletons represent a class of AIEgens with acceptor-donor-acceptor configuration,which generated the desired twisted intramolecular charge transfer(TICT)AIE properties and could be used as fluorescent probes for detecting the micrometer-sized phase separation of polymer blends.The protocol provides a concise route for the synthesis and application of carbazole-based AIE luminogens.
基金supported by the National Natural Science Foundation of China(Nos.22073066,21503143 and 21975179)the Natural Science Foundation of Tianjin(No.16JCQNJC05600)。
文摘Density functional theory calculations have been performed to investigate the dipeptide phosphinecatalyzed hydroamination of enones with pyridazinones.The computations reveal that a number of the N-H...O hydrogen-bonding interactions with the pyridazinone moiety and the C–H...O hydrogenbonding interactions with the enone moiety are present in the enantioselectivity-determining Michael addition transition states.The experimentally-observed catalyst-controlled enantiodivergence is mainly attributed to the significant impact of the substituent of the amide moiety of the dipeptide phosphine on the relative strength of the N-H...O hydrogen-bonding interactions,which was found to affect the Si face attack transition state,enabling the enantioselectivity switch upon change of chiral dipeptide phosphine catalyst.
基金supported by the National Natural Science Foundation of China(Nos.22073066,21503143 and 21975179)。
文摘Density functional theory calculations have been performed to investigate the nickel-catalyzed[3+2]cycloaddition of cyclopropenones andα,β-unsaturated ketones.The computations show that the overall catalytic cycle consists of four major steps,including:(1)C-C oxidative addition of the cyclopropenone to afford the four-membered nickelacycle,(2)isomerization,(3)migratory insertion via a 4,1-insertion fashion,and(4)C-C reductive elimination to deliver the[3+2]cycloaddition product.The enantioselectivity is mainly attributed to the p-p interaction between the diphenylcyclopropenone moiety and the phenyl substituent of the oxazoline ring of the ligand.The chemoselectivity of the C=O versus C=C insertion was rationalized in terms of the steric effect.
基金supported by the National Natural Science Foundation of China(Nos.22073066,21503143 and 21975179)the Natural Science Foundation of Tianjin(No.16JCQNJC05600)。
文摘Density functional theory calculations have been performed to investigate the copper-catalyzed borocyanation of 1-aryl-1,3-butadienes.The computations show that the regio-and enantioselectivity is determined by the borocupration step.The π-electron withdrawing aryl group at the C' atom makes the C4 atom more electrophilic than the other carbon atoms,which together with the steric repulsion around the forming C-B bond,re sults in the experimentally observed exclusive 4,3-regioselectivity.The origins of the enantioselectivity were attributed to the steric effect and π-π stacking interaction between the butadiene moiety and the ligand.
基金supported by the National Natural Science Foundation of China(No.21503143)the Tianjin Natural Science Foundation(Nos.16JCQNJC05600 and 16JCYBJC43600)+1 种基金the Talent Research Start-up Fund of Tianjin Normal University(No.5RL139)support from the Shenzhen Peacock Plan(No.1208040050847074)
文摘The rhodium-catalyzed formal C（sp^3）-H activation/spiroannulation of α-arylidene pyrazolones with alkynes was investigated by means of density functional theory calculations. The calculations indicate that the spiroannulation through the proposed C-C reductive elimination is kinetically unfeasible, Instead, the C-C coupling from the eight-membered rhodacycle was proposed to account for the experimental results. The overall catalytic cycle consists of six steps： （1） the keto-enol isomerization; （2） the O-H deprotonation, （3） the C（sp^2）-H bond cleavage; （4） the migratory insertion of alkyne into the Rh-C bond; （5） the C-C coupling and （6） the regeneration of the active catalyst.
基金supported by the National Natural Science Foundation of China(21901185,22073066,22471191,22201062)the Natural Science Foundation of Tianjin(23JCYBJC00760)the funds provided by Tianjin Normal University。
文摘The development of olefin hydroacylation with easily accessible acyl reagents in a regioselective manner is highly desirable yet challenging.Herein,we report the hydroacylation of alkenes using acid chlorides as both acyl reagents and endogenous oxidants through a hydrogen atom transfer pathway.Exclusive Markovnikov hydroacylation of a wide range of alkenes,including terminal,internal,1,1-disubstituted alkenes,and even light gaseous olefins,with aryl and alkyl acid chloride,was achieved with the use of a biquinoline ligand.The direct and step-economy hydroacylation reveals a distinct regioselectivity and ligand dependence compared to traditional NiH chemistry.This protocol has attractive features such as the low cost,broad substrate scope,mild conditions,and easy operation,providing an efficient and modular access to branched ketones with diverse architectures.Density functional theory calculations suggest that the reaction proceeds via a hydrogen atom transfer(HAT)mechanism followed by outer-sphere C–C reductive elimination.
基金the National Natural Science Foundation of China(22201087,22073066,22471191)for the financial support。
文摘Chiralγ-amino acids are among the most valuable and ubiquitous structural units in natural products,pharmaceuticals and many physiologically active compounds.Herein,we demonstrate a convenient synthetic approach to chiralγ-amino acid structures via an asymmetric aryl-aminoalkylation of alkenes enabled by a dual photoredox/nickel catalysis.Taking advantage of the mild and redox-neutral condition,high levels of enantiocontrol ofα-carbonyl benzylic stereocenters are obtained.Experimental and computational mechanistic studies were performed to gain insights into the mechanism and origin of enantioselectivity.The results reveal that the reaction follows a Ni(0)/Ni(I)/Ni(III)/Ni(I)catalytic cycle and C-X bond oxidative addition is the enantiodetermining step.
基金supported by the National Natural Science Foundation of China(Nos.22471191,22073066,and 22271134)Shenzhen Science and Technology Innovation Commission(Nos.RCJC20221008092723013,JCYJ20230807093104009).
文摘Density functional theory calculations were performed to investigate the iridium-catalyzed atroposelective intermolecular C-H silylation of 2-arylisoquinolines.The Ir(Ⅲ)hydride species was identified as the active catalyst species of the reaction.The computations show that the reaction occurs through the Ir(Ⅲ)/Ir(Ⅴ)catalytic cycle.The C(sp^(2))-H oxidative addition represents the rate-and enantioselectivity-determining step.The distortion/interaction and structural analyses reveal that the BINEPINE skeleton of the PSiSi ligand creates an axially chiral pocket for the C-H oxidative addition,providing a ligand-enabled axial chirality transfer strategy responsible for the observed enantioselectivity.The match/mismatch in axial chirality between reacting 2-arylisoquinolines and the BINEPINE skeleton of the PSiSi ligand plays a key role in governing enantioselectivity.
基金supported by Tianjin University(B22021-010)the State Key Laboratory of Elemento-Organic Chemistrythe National Natural Science Foundation of China(22371203,22073066,21503143,21975179)。
文摘The Ni-catalyzed highly selective diborylative cyclization of 1,6-enynes with diboron reagent has been developed. When pinB-Bdan was used, multiple types of boron-containing functional groups could be installed into organic molecule with great chemoselectivity and regioselectivity though this reaction. Meanwhile, if B_2pai_2 was employed, the asymmetric diborylative cyclization could be well induced by using strategy of dynamic kinetic resolution. Importantly, the above reactions could afford desired product with 100% atomic economy, and could be compatible with different series of substituents. The studies of further transformation well illustrated that different type products could serve diverse synthetic strategy. Notably, the reaction mechanism was intensively studied by density functional theory(DFT) calculations, which could reveal the mechanism of regio- and enantio-selective control.
基金support is from Tianjin University,State Key Laboratory of Elemento-Organic Chemistry,and the National Natural Science Foundation of China(Nos.21801181,22073066,21503143 and 21975179).
文摘The palladium-catalyzed borylative cyclization via C—H activation has been developed.By this chemistry,the indole-fused dihydro-pyrrole motif,which is a kind of important unit in natural products and bio-active molecules,could be constructed and installed with a boric ester group.Furthermore,the utilities of products have been illustrated by the study of further transformations.Importantly,by using chiral ligand,the enantioselectivity of this borylative cyclization reaction could be controlled.Moreover,the borylative mechanism,which should proceed through a Pd(II)/Pd(IV)catalytic cycle,has been proposed based on the DFT calculations.
文摘Objective:In this study,we summarize the clinical characteristics and neonatal outcomes of patients with pregnancy luteomas that were identified incidentally at cesarean section in our hospital.We also provide a review of the existing literature relating to this condition.Methods:A total of seven cases of pregnancy luteoma were enrolled from our hospital into this retrospective study between March 2013 and February 2018.We then evaluated the clinical characteristics and neonatal outcomes of these patients.Results:All seven patients with pregnancy luteomas found incidentally during Cesarean sections at term as a result of obstetric indications.These masses were unilateral and ranged from 2 to 10 cm in size.All patients underwent partial ovariectomies or oophorocystectomy due to presumptive benign ovarian tumors.Two patients had gestational diabetes and one patient had gestational hypertension.One patient developed hirsutism and a deepened voice.Of the seven newborns,three were girls and four were boys.Physical examinations of the newborns were normal and no virilization was detected among the infant girls.Conclusion:Pregnancy luteoma may be more common than expected.Better strategies are now needed to educate obstetricians about the clinical features of pregnancy luteoma so that they can avoid unnecessary surgery.
